Add tracking for exec session IDs

Exec sessions now have an ID generated and assigned to their PID
and stored in the database state. This allows us to track what
exec sessions are currently active.

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

Closes: #412
Approved by: baude

1 files changed, 29 insertions, 0 deletions

diff --git a/libpod/util.go b/libpod/util.go
index 0c6700fbf..ca93fc097 100644
--- a/libpod/util.go
+++ b/libpod/util.go
@@ -107,3 +107,32 @@ func MountExists(specMounts []spec.Mount, dest string) bool {
 	}
 	return false
 }
+
+// WaitForFile waits until a file has been created or the given timeout has occurred
+func WaitForFile(path string, timeout time.Duration) error {
+	done := make(chan struct{})
+	chControl := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case <-chControl:
+				return
+			default:
+				_, err := os.Stat(path)
+				if err == nil {
+					close(done)
+					return
+				}
+				time.Sleep(25 * time.Millisecond)
+			}
+		}
+	}()
+
+	select {
+	case <-done:
+		return nil
+	case <-time.After(timeout):
+		close(chControl)
+		return errors.Wrapf(ErrInternal, "timed out waiting for file %s", path)
+	}
+}